Important Note:Plantronics Polaris Headsets can only be use with telephones with a headset jack built-in (ie. Nortel, NEC, etc).DO NOT BUY THIS HEADSET WITH A VISTA M12 or M22 AMPLIFIER.If your phone does not have a headset jack and internal amplifier, then the Plantronics H-Series Headsets with an external amplifier such as the Plantronics Vista M22are a good solution.